Chemistry - Online Test
Q1. The furnace which gives the highest temperature is
Answer : Option D
Explaination / Solution:
Blast furnance maintains the highest temperature.
Q2. Which of the following is Paramagnetic?
Answer : Option D
Explaination / Solution:
NO is paramagnetic. Its unpaired electron is present in antibonding orbital.
Q3. The process by which impurity is introduced in semiconductors to enhance its conductivity is known as
Answer : Option D
Explaination / Solution:
Semiconductors are doped with impurities to enhance conductivity.
Q4. One of the following options is not used for explaining atomic radius
Answer : Option D
Explaination / Solution:
The distance from centre of the nucleus to the outermost shell containing the electrons is called atomic radius. There are four types that are widely used: covalent radii, metallic radii, van der Waal's radii and ionic radii.
Q5. Which of the following statements is not true about low density polythene?
Answer : Option B
Explaination / Solution:
Low density polymer are poor conductor of electricity.
Q6. Radio frequency region of the electromagnetic spectrum is used for broadcasting. It is
Answer : Option D
Explaination / Solution:
Radio frequency (RF) is any of the electromagnetic wave frequencies that lie in the range extending from around3 kHz to 300 GHz, which include those frequencies used in radio communication or radar. RF usually refers to electrical rather than mechanical oscillations
Q7. Chemical species present in the environment are either naturally occurring or generated by human activities. Their interrelation with the surroundings is called :
Answer : Option A
Explaination / Solution:
environmental chemistry basically deals with the interrelationship between chemical species generated by human activities or naturally.
Q8. Which shows maximum magnetic moment among the bivalent ions of the first transition series?
Answer : Option B
Explaination / Solution:
Mn2+ has d5 configuration so maximum no. of un paired electrons.
Q9. In Calgon’s method, one of the following chemical is used to remove hardness of water
Answer : Option C
Explaination / Solution:
Sodium hexametaphosphate is called calgon. Its molecular formula is (NaPO3)6 or Na6P6O18.
The addition of Calgon to hard water causes the calcium and magnesium ions of hard water to displace sodium ions from the anion of Calgon. This results in the removal of calcium and magnesium ions from hard water in the form of a complex with Calgon. The water is softened and sodium ions are released into water.
Q10. A mixture of benzaldehyde and formaldehyde on heating with aqueous NaOH solution gives
Answer : Option C
Explaination / Solution:
They will undergo cannizaro reaction.
